This invention relates to an electrostatic air cleaning apparatus, and in particular, to a type having a collecting section, including a first charged grid, and a second grounded grid sandwiching therebetween a sheet of foraminous filter media.
As is known to those skilled in the art, electrostatic precipitation or air cleaning apparatus are generally installed as part of duct systems employed with forced air heating and/or cooling apparatus serving enclosures such as residences or the like. The apparatus generally includes a power pack which transforms conventional household AC voltage to a DC power source of substantial voltage. The increased DC voltage is applied to ionizer and collector sections of the apparatus for the purpose of creating electrostatic fields in the area traversed by the air stream flowing through the duct system.
Generally, the ionizer section comprises a plurality of wires, each of which is disposed adjacent a plate so as to define a plurality of passages, each with an electrostatic field disposed therein. The electrostatic fields thus formed are of a magnitude that a corona discharge is generated from the wire. Particles of dirt or dust entrained in air flowing within the plurality of passages receive an electrical charge of a particular plurality to enable such dirt to be readily removed from the air stream at the collector section of the apparatus.
The collector section of the apparatus generally comprises a plurality of alternately charged and grounded members having electrostatic field created therebetween whereat the charged particles are removed from the air stream and collected. A first form of collector section comprises a plurality of alternately charged and grounded plates. Another form of collector section comprises alternately charged and grounded grids sandwiching a suitable foraminous filter media. The present invention is particularly suitable for use with collector sections of the second type.
Although electrostatic air cleaning apparatus are considerably more efficient than mechanical filters in removing dirt and other foreign particles entrapped in an air stream, the initial cost of such apparatus has somewhat discouraged the potential consumers from obtaining such apparatus. Accordingly, manufacturers of such apparatus have attempted to reduce the cost thereof. However, in some cases, attempted cost reductions have resulted in poor performing apparatus.
In addition, one of the grids forming the collector section must be made movable to permit the filter media to be removed for cleaning or replacement purposes. If the movable grid is not accurately repositioned with respect to the stationary grid, non-uniform electrostatic fields will be generated resulting in inefficient operation of the apparatus.